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Hey everyone, I've just upgraded from my Intel Arc A380 to the new B580. Everything works fine, and it's using the new "Xe" driver. Looking at lspci, it seems the new B-Series doesn't even support the legacy i915 drivers.
Anyway, in KDE Wayland session, I always get half the framerate. So when choosing 60Hz, it runs at 30Hz, and at 75Hz, it's 38Hz. I've been googling for hours now and couldn't find any solutions.
It works just fine on X11.
Intel Arc B580:
03:00.0 VGA compatible controller: Intel Corporation Battlemage G21 [Arc B580] (prog-if 00 [VGA controller])
Subsystem: Intel Corporation Device 1100
Flags: bus master, fast devsel, latency 0, IRQ 161
Memory at 82000000 (64-bit, non-prefetchable) [size=16M]
Memory at 4000000000 (64-bit, prefetchable) [size=16G]
Expansion ROM at 83000000 [disabled] [size=2M]
Capabilities: [40] Vendor Specific Information: Len=0c <?>
Capabilities: [70] Express Endpoint, IntMsgNum 0
Capabilities: [ac] MSI: Enable+ Count=1/1 Maskable+ 64bit+
Capabilities: [d0] Power Management version 3
Capabilities: [100] Alternative Routing-ID Interpretation (ARI)
Capabilities: [110] Null
Capabilities: [200] Address Translation Service (ATS)
Capabilities: [420] Physical Resizable BAR
Capabilities: [400] Latency Tolerance Reporting
Kernel driver in use: xe
Kernel modules: xe
Resolution options:
Screen 0: minimum 16 x 16, current 2560 x 1440, maximum 32767 x 32767
DP-1 connected primary 2560x1440+0+0 (normal left inverted right x axis y axis) 597mm x 336mm
2560x1440 74.89*+
1920x1440 74.89
1600x1200 74.88
1440x1080 74.92
1400x1050 74.87
1280x1024 74.90
1280x960 74.86
1152x864 74.82
1024x768 74.67
800x600 74.91
640x480 74.77
320x240 73.82
1920x1200 74.93
1680x1050 74.89
1440x900 74.85
1280x800 74.76
1152x720 74.72
960x600 74.84
928x580 74.58
800x500 74.87
768x480 74.71
720x480 74.51
640x400 74.23
320x200 72.67
2048x1152 74.89
1920x1080 74.91
1600x900 74.89
1368x768 74.73
1280x720 74.78
1024x576 74.80
864x486 74.45
720x400 74.23
640x350 74.53
Last edited by Gravarty (2025-04-02 13:42:30)
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the same problem
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Found it. https://bugs.kde.org/show_bug.cgi?id=500219
TL;DR this is a driver-side issue with pageflips taking longer than expected. For now, use the workaround of setting KWIN_DRM_OVERRIDE_SAFETY_MARGIN. Someone with a 165Hz display had luck setting it to 2200, but I also with a 75Hz display had to set it a little higher for it to stop dropping frames. 3000 3500 seems to do the trick.
It's worth noting that this only affects compositing. So, if you're running a video player or a game in fullscreen that supports direct scanout (direct scanout must be enabled in the Display settings via "Screen tearing: Allow in fullscreen windows"), then you will get full framerate in those programs even without the workaround.
Last edited by anh0516 (2025-05-21 19:19:03)
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https://invent.kde.org/plasma/kwin/-/me … uests/7438
This commit temporarily fixes the issue.
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